PCI: faraday: Add clock bindings

The Faraday FTPCI100 controller has two clock ports, PCLK and PCICLK.  Add
bindings for these two clocks so we can assign them in the device tree.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rob Herring <robh@kernel.org>